Antenna system



Jan. -10, 1950 POSTHUMUS 2,494,198

ANTENNA SYSTEM Filed April 24, 1946 KLASS POSJHUMUS INVENTOR.

AT T ORNFK Patented Jan. 10, 1950 2394498 ANTENNA SYSTEM KlaasPosthumus,

signer, by

Eindhoven, I mesne assignments, to Hartford N etherlanda. as-

National' Bank and Trust .Company, Hartford,

Conn, as'trustee Application April 2.4

vInethe Netherlands, October 2,1942 Section 1, PublioLaw Fatent expires6 Claims. (01. 25033.51.

In an antenna system comprising a conductor wherein solely travellingwaves may appear, it is known that this conductor can be replaced, foravoiding the losses occurring in the necessary terminating resistance,by two juxtaposed parallel conductors which are arranged at a smalldistance from each other, say Ta orless of the operating wave length,and are excited in such manner that stationary waves displaced in phaseby 90 appear in them.

The present invention has for its object. toprovide an extremelysuitable method of connecting and arranging the feed conductors in anantenna system comprising such a pair of-cond-uctors.

According to the invention, one conductor of the pair of conductors isinterrupted atsa current loop, which occurs at a point preferably midwaythe ends, and the connecting terminals thus formed are respectivelyconnected to the conductors of a twin-core feed line, the otherconductor being connected to a single-core feed conductor at the voltageloop which occurs at the point corresponding to the point ofinterruption.

In order to avoid radiation coupling between the two feed systemspreferably the single-core feed conductor is provided midway between theconductors of the twin-core feed line.

The invention will be more fully explained by reference to theaccompanying drawing representing, by way of example, an antenna systemaccording thereto.

In the sole figure the reference number designates a half-rhomb antennalocated in a horizontal plane for the emission of oscillations to betransmitted mainly in the horizontal direction indicated by the arrow 2.The antenna is composed, in a manner known per se, of two juxtaposedparallel conductors 3, 3' and i, 4 which are arranged at a smalldistance from each other so that they are strongly coupled by radiation.The conductors 3, 3' and t, 4', each of which has a length of say 4i\=operating wave length) should be excited in such manner thatstationary waves displaced in phase by 90 appear therein.

The ends of the conductor 3, 3', in contradistinction to those of theconductor 4, 4, are earthed so that, since the length of the conductorsis a whole multiple of the operating wave length, a current loop occursat the middle of the conductor 3, 3, whereas a voltage loop occurs atthe middle of the conductor 6, 4'.

The conductor 3, 3' is interrupted at the middle where it is connectedto a feed line 5 consisting of two conductors, while the middle of the690-, AuguSt8,'-'1946 umber-2,1396% conductor 6 areinductwel-y coupled,with coils 8 and 9 respectively which are connected to a transmitter 1 adisplaced in phase by In thisway the conductor halves '3 andt fed inpush-pull, whereas the .4 and 3- are fed in parallel with a phasedisplacementofeo with respecttothe conductor halves 3 and 3'.

-What-.L claim. is

1. An antenna system comprising first and second radiating conductors:juxtaposed in par allel rel-ationtand, having respective lengthssubstantially equal to a whole multiple of the operating wave-length ofthe antenna system, said mediate wire of said line being connected tothe midpoint of said second conductor.

2. An antenna system comprising first and second radiating conductorsjuxtaposed in parmeans for applying voltages displaced in phase line,and means for and a transmission line for feeding said conuctors, saidline being formed by three equispaced parallel wires, the outer wires ofsaid line {being connected to said input terminals and the center wirebeing connected to the midpoint of said second conducto .7

4. An antenna system comprising first and second radiating conductorsjuxtaposed in par spaced parallel wires, the outer wires of said line Ibeing connected to said input terminals and the center wire beingconnected to the midpoint of f for applying radio said second conductor,means frequency voltages of a predetermined wavelength and displaced180' in phase from each other to the two outer wires of said line, andmeans for applying a radio frequency voltage of said wavelength anddisplaced 90 in phase from the voltages in the outer wires to the centerwire of said line.

5. An antenna system adapted to be energized from a source of highfrequency voltage having a predetermined wavelength, said systemcomprising first and second radiating conductors juxtaposed in parallelrelation each having a total length substantially equal to a wholemultiple of the operating wavelength of said system, said firstconductor being divided at the midpoint thereof to provide inputterminals thereto, said first conductor being directly grounded at theextremes thereof, a transmission line for feeding said conductors, saidlines being formed by three parallel wires, the two outer wires of saidline being connected to said input terminals and the intermediate wirebeing connected to the midpoint of said second conductor, a firsttransformer having a primary connected to the voltage source and acentertapped secondary whose ends are connected to said outer wires andwhose centertap is grounded, and asecond transformer having a primaryconnected to the voltage source and a secondari having one end thereofconnected to said intermediate wire and the other end thereof grounded.

6. An antenna system as set forth in claim 5 wherein the axes of saidfirst and second parallel conductors are arranged in an oblique anglewhose apex is the midpoints thereof whereby said conductors form ahalf-rhombic antenna.

KLAAS POSTHUMUS.

REFERENCES CITED The following references are of record in the

